Rigless intervention

ABSTRACT

A method comprising providing a first vessel floating on a surface of a body of water; connecting a first line from the first vessel to a subsea structure; lifting the subsea structure within the body of water; connecting a second line from a second vessel to the subsea structure; disconnecting the first line from the subsea structure; and lifting subsea structure to the second vessel with the second line.

BACKGROUND OF INVENTION

1. Field of the Invention

The invention is directed to systems and methods for installing and/or retrieving subsea components without the use of a drilling rig.

2. Background Art

Currently, sub-sea equipment (e.g., submersible pumps, manifolds, and trees) may be deployed and/or retrieved using a semi-submersible drilling rig. Typically, the drilling rigs are configured to hoist the sub-sea equipment from the ocean floor to the surface through the use of cables and lines. Once the sub-sea equipment has reached the surface, it may be lifted through an opening in the center of the rig (e.g., moon pool) and onto the deck of the drilling rig. As such, the piece of sub-sea equipment being retrieved or deployed may be susceptible to being damaged during transportation. Further, drilling rigs are extremely expensive to operate, costing around $600,000-$800,000/day to lease and operate. Furthermore, drilling rigs are transported at a slow rate when compared to other floating vessels (e.g., ships, tug boats), which may increase the amount of time it takes to retrieve and/or deploy sub-sea equipment. Accordingly, there exists a need for an efficient and cost effective system to retrieve and/or deploy sub-sea equipment.

U.S. Patent Application Publication Number 2003/0221602 discloses an alternative for deploying and installing subsea equipment using a workboat or other vessel of opportunity. The equipment is not supported directly by the vessel, but is instead supported by one or more buoys below the wave zone. The buoys are controlled by a combination of chain, wire rope, and synthetic line linking it to the workboat. As such, the buoy system described therein decouples vessel motion from the payload by supporting the payload from the buoys below the wave zone. Because the buoys are below the wave action and its associated turbulence, there is little energy and hence little tendency for motion. The result is a stable, inexpensive, maneuverable system capable of servicing large subsea payloads in a wide range of water depths. U.S. Patent Application Publication Number 2003/0221602 is herein incorporated by reference in its entirety.

U.S. Pat. No. 7,314,084 discloses a system comprising a pumping module coupled to an intermediate flow inlet (IFI) wherein said IFI is coupled to a base structure disposed on the flow line that routes production from one or more oil wells, allowing for the quick and easy installation or recovery of a subsea pumping module by cable from an inexpensive vessel. The disclosure also provides for the hydraulic isolation of the subsea pumping module by means of on-off valves on the IFI whereby the pumping module can be easily installed or removed without causing underwater oil spills. Sealing of the connection is of the metal-metal type. It is also possible to pass a pig through the system for clearing the flow lines. U.S. Pat. No. 7,314,084 is herein incorporated by reference in its entirety.

U.S. Pat. No. 7,150,325 discloses a subsea pumping assembly located on a seafloor for pumping well fluid from subsea wells to the level. The pumping assembly has a tubular outer housing that is at least partially embedded in the seafloor. A tubular primary housing located in the outer housing and has a lower end with a receptacle. An annular space surrounds the primary housing within the outer housing for delivering fluid to a receptacle at the lower end of the primary housing. A capsule is lowered in and retrieved from the primary housing. The capsule sealingly engages the receptacle for receiving well fluid from the annular space. A submersible pump is located inside the capsule. The pump has an intake that receives well fluid and a discharge that discharges the well fluid exterior of this capsule. The capsule has a valve in its inlet that when closed prevents leakage of well fluid from the capsule. The capsule may be retrieved through open sea without a riser. U.S. Pat. No. 7,150,325 is herein incorporated by reference in its entirety.

U.S. Patent Application Publication Number 2005/0220645 discloses a booster pumping system for producing hydrocarbons from a subsea production well. The booster pumping system includes: (1) a submersible pump hydraulically connected to the production well to provide energy to the hydrocarbon flow and boost production to another destination such as a subsea production facility or the surface via a riser; (2) an inlet conduit to receive the flow from the production well and isolate the flow from the dummy wellbore and direct the flow to the intake of the pump; and (3) a motor exposed to the dummy wellbore to drive the pump. The dummy wellbore may be flooded or circulated with seawater to cool the motor. U.S. Patent Application Publication Number 2005/0220645 is herein incorporated by reference in its entirety.

U.S. Patent Application Publication Number 2006/0118310 discloses a subsea production system for producing petroleum by artificial elevation, assisted by submersible centrifugal pumps (SCPs) upstream of the WCT and installed on the seabed, including a pumping module having one of more SCPs, installed in series or in parallel, with an inclination of up to 85 degrees in relation to the vertical, the module being connectible to a flow base to permit the “bypass” of production and wherein the pumping module and the flow base may be linked to installation and recovery by cable. A production line is connected upstream to the pumping module upstream and another production line is connected downstream to the pumping module. A method of installing the system in a new wellhead is described, as well as a method for installing the system in an existing wellhead. The uses of the subsea production system for boosting multiphase flow, injection of water in an injector well and the transfer of oil between two points of collection are also described. U.S. Patent Application Publication Number 2006/0118310 is herein incorporated by reference in its entirety.

U.S. Patent Application Publication Number 2008/0314598 discloses a system for installation of a subsea module of great length by means of a vessel, using a cable for its installation and/or retrieval, and methods applied therein. The system allows transporting the subsea module on the vessel to a location in the sea and descending the subsea module into the sea at a vertical position for installation on the seabed. U.S. Patent Application Publication Number 2008/0314598 is herein incorporated by reference in its entirety.

SUMMARY OF THE INVENTION

One aspect of the invention provides a method comprising providing a first vessel floating on a surface of a body of water; connecting a first line from the first vessel to a subsea structure; lifting the subsea structure within the body of water; connecting a second line from a second vessel to the subsea structure; disconnecting the first line from the subsea structure; and lifting subsea structure to the second vessel with the second line.

Another aspect of the invention provides a method comprising providing a first vessel floating on a surface of a body of water; connecting a first line from the first vessel to a subsea structure; lowering the subsea structure within the body of water; connecting a second line from a second vessel to the subsea structure; disconnecting the first line from the subsea structure; moving the second vessel, the second line, and the subsea structure to a desired installation location; and installing the subsea structure at the desired location within the body of water.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1-8 show a retrieval and/or deployment system for an electric submersible pump (ESP) caisson in accordance with embodiments of the present disclosure.

FIG. 9 shows an elevation view of a retrieved ESP caisson in accordance with embodiments of the present disclosure.

DETAILED DESCRIPTION

In one aspect, embodiments disclosed herein relate to a method of retrieving and deploying subsea equipment, such as an electric submersible pump (ESP) caisson. Specifically, embodiments disclosed herein relate to a method of using a workboat and a side deck of a floating production, storage, and offloading vessel (FPSO) to retrieve, deploy, and/or service an ESP.

FIG. 1:

Referring initially to FIG. 1, a system for attaching a piece of subsea equipment 100 to a workboat 102 according to embodiments of the present disclosure is shown. In this embodiment, a piece of subsea equipment 100 is located at and/or below the mudline 101. When repairs, upgrades, replacement, or other operations known in the art require an installation, retrieval, or other intervention, a workboat 102 may be connected to the piece of subsea equipment 100 via a line 104 and a connector 103. The workboat 102 may include a lifting device 116 such as a crane, winch, hoist or other lifting device known in the art. The line 104 is preferably a line having a high elastic limit and high strength to weight ratio, such as a torque balanced wire rope, but it may also include chains, cables, wires, ropes, or other retrieval or deployment devices known in the art. The connector 103 may be a threaded connector, an interference fit connector, a swivel, a hook, or other connection device known in the art. In one embodiment disclosed herein, the connector 103 may connect line 104 to a substantially rigid structure affixed to the body of the piece of subsea equipment 100. Additionally, in another embodiment disclosed herein, connector 103 may connect line 104 to a line/cable or series of lines/cables connected to the piece of subsea equipment 100. Those of ordinary skill in the art will appreciate the wide variety of available lifting devices, lines, and connectors that are available and may be used to attach the piece of subsea equipment 100 to the workboat 102 without departing from the scope of embodiments disclosed herein.

In one embodiment, piece of subsea equipment 100 may be below the mudline such as a caisson separator, a submersible pump, or other known equipment. In another embodiment, piece of subsea equipment 100 may be above the mudline such as a subsea separator, a wellhead, a Christmas tree, a manifold, or other known equipment.

FIGS. 2 & 3:

Referring now to FIGS. 2 and 3, a system for recovering the piece of subsea equipment 100 from the wellbore and transporting the piece of subsea equipment 100 to the FPSO 106 is illustrated. In one embodiment, the piece of subsea equipment may be removed from a template disposed in a main wellbore. The lifting device 116 disposed on the workboat 102 raises the piece of subsea equipment 100 from the wellbore by drawing in the line 104. The lifting device 116 may be a winch, a crane, a heave compensated lift system, or other lifting devices as are known in the art. The recovery of the line may be to a transport depth at which point the workboat 102 transports the piece of subsea equipment 100 to the FPSO 106. The transport depth may be determined by safety factors such as subsea formations, manmade installations, water currents, water surface conditions, weather, speed of transport, capabilities of equipment, or other appropriate factors that may influence the depth of transport. Furthermore, the depth may be determined by financial factors such as efficiency of the workboat, number of crew members, wear on equipment or other factors which may affect operating costs. In one embodiment, a suitable transport depth for a bottom of the subsea equipment 100 may be from about 100 to about 500 meters, for example from about 250 to about 350 meters.

FIG. 4:

Referring now to FIG. 4, a system for recovering the piece of subsea equipment 100 to a hand off depth is illustrated. The hand off depth is the depth at which a second line is connected to the caisson and may or may not be the same as the transport depth. The second line during recovery, for example, may be a line 108 connected to a FPSO 106. The hand off depth may be determined by water currents, surface conditions, weather conditions, equipment operating depths, or other reasons known in the art. The lifting device 116 of the workboat 102 may recover the caisson 100 by adjusting the length of line 104 to a specific depth by drawing in or letting out length of line 104. A line 108 connected to the FPSO 106 may then be let out to a handoff depth that is at least as long or deep as the suspended workboat line 104. The FPSO line 108 is attached to a lifting device 216 such as a crane, winch, hoist or other lifting device known in the art. The FPSO line 108 may be a rope, cable, chain, or other retrieval or deployment device known in the art.

In one embodiment, a suitable handoff depth for a bottom of the subsea equipment 100 may be from about 100 to about 500 meters, for example from about 200 to about 400 meters.

Although an FPSO 106 is illustrated in FIG. 4, other floating systems may also be used to retrieve the equipment 100, such as a spar, TLP, semisub, ship, or other floating moored or unmoored oil and gas drilling and/or production vessels.

FIG. 5:

Referring to FIG. 5, a system for connecting the piece of subsea equipment 100 to the FPSO 106 according to embodiments of the present disclosure is shown. Initially the workboat 102 and the corresponding line 104 support the loads of the Piece of subsea equipment 100. The lifting device 216 of the FPSO 106 is attached to a first end of the line 108. A free end of the line 108 is suspended in the water and has an FPSO connector 203. A manned underwater vehicle such as a submarine or unmanned underwater vehicle

(UUV), such as a remotely operated vehicle (ROV) 110 may be used to attach the FPSO line 108 to the piece of subsea equipment 100 via the FPSO connector 203.

In one embodiment disclosed herein, the connector 203 may connect line 108 to a substantially rigid structure affixed to the body of the piece of subsea equipment 100. Additionally, in other embodiments, FPSO connector 203 may connect line 108 to a line/cable or series of lines/cables connected to the piece of subsea equipment 100. The FPSO connector 203 may be a threaded connector, an interference fit connector, a swivel, a hook, or other connection device known in the art. The FPSO connector 203 may or may not be the same type of connector as the workboat connector 103. In one embodiment of the present disclosure, the FPSO connector 203 may connect FPSO line 108 to the same feature of piece of subsea equipment 100 as the workboat connector 103, where the feature may be, as described above, a substantially rigid structure, line/cable, or other element of the piece of subsea equipment 100.

In another embodiment disclosed herein, the FPSO connector 203 may connect FPSO line 108 to a different feature of the piece of subsea equipment 100 disposed in a different location or orientation than the workboat connector 103. Additionally, the ROV 110 may be used to monitor and/or assist with lowering, raising, and/or positioning equipment in the water.

In one embodiment, workboat connector 103 may be connected to the top of equipment 100, while FPSO connector 203 may be connected to the bottom of equipment 100, so that when FPSO line 108 is pulled in, equipment 100 is turned upside down.

FIG. 6:

In the embodiment shown in FIG. 6, a system for transferring the piece of subsea equipment 100 from the workboat 102 to the FPSO 106 is shown. After the FPSO line 108 is attached to the connector 203 of the caisson 100, for example with an ROV 110, a transfer of the piece of subsea equipment from the workboat to the FPSO may take place. The transfer of the load may occur by increasing the length of the workboat line 104, decreasing the length of the FPSO line 108, or a combination of the two. Adjustment of the lengths of the FPSO line 108 and/or the workboat line 104 may be accomplished through the lifting devices 116, 216 (FIG. 4) located on the FPSO 106 and workboat 102. When the length of one of the FPSO line 108 or workboat line 104 is increased/decreased, such that the FPSO line 108 or workboat line 104 is longer than the other line, the load of the caisson is transferred to the structure, i.e., work boat 102 or FPSO 106, supporting the shorter line. Thus, after the FPSO line 108 is in tension from supporting the caisson 100 load, the ROV 110 may release the workboat line 104 from the piece of subsea equipment 100, or workboat line 104 may be released by personnel on FPSO 106 when equipment 100 is brought up to FPSO 106.

FIG. 7:

Referring now to FIG. 7, a system for lifting the piece of subsea equipment 100 to a support platform 112 of the FPSO 106 is illustrated. Lifting device 216 on the FPSO 106 may lift the piece of subsea equipment 100 by decreasing the length of the FPSO line 108 extending into the sea. Additionally, the length of line 108 may be decreased by drawing in line 108 with a winch or various other means known in the art. The top of the piece of subsea equipment 100 may rise above the surface of the water.

FIG. 8:

In the embodiment shown in FIG. 8, a system for securing the piece of subsea equipment 100 to the FPSO 106 is shown. The piece of subsea equipment 100 is suspended from the lifting device 216. In the embodiment shown, the lifting device 216 is a crane system, but as previously stated it may also be a winch, hoist, or other lifting device known in the art without departing from the scope of the present disclosure. The piece of subsea equipment 100 may be maneuvered by any necessary means in translational or rotational directions in order to land the equipment 100 within a holding bracket 118. Holding bracket 118 is secured to a side of FPSO 106 and is configured to receive and secure piece of subsea equipment 100 to FPSO 106. Those of ordinary skill in the art will appreciate the many types of brackets and locking mechanisms that may be used to secure the piece of subsea equipment without departing from the scope of the present disclosure.

FIG. 9:

Referring to FIG. 9, an elevation view of a retrieved piece of subsea equipment 100 positioned on the support platform 112 of the FPSO 106 is shown. The piece of subsea equipment 100 may be repaired, upgraded, stored, serviced, or replaced on the deck of the FPSO 106. The lifting device 216 may be disconnected and used for other operations.

Equipment Deployment:

Additionally, referring generally to FIGS. 1-9, a method similar to those described above may be used to deploy a piece of subsea equipment 100. During deployment, the piece of subsea equipment 100 is connected to the lifting device 216 of the FPSO 106 via a line 108. The connector 203 may be one of many different types previously described. The piece of subsea equipment 100 may be released from the bracket 118 and lowered to the hand off depth. Lifting device 116 disposed on workboat 102 lowers the line 104 to at least the hand off depth. The ROV 110 may attach the workboat line 104 using any suitable connector 103 known in the art. Transferring the piece of subsea equipment 100 load from the FPSO 106 to the workboat 102 may be accomplished by letting out the FPSO line 108, drawing in the workboat line 104, or a combination of the two. The ROV 110 may then disconnect the FPSO line 108 from the connector 203 and the workboat 102 may let out or draw in line 104 to position the Piece of subsea equipment 100 at a transport depth. The workboat 102 transports the Piece of subsea equipment 100 to the wellbore location where the workboat line 104 is let out to lower the Piece of subsea equipment 100 closer to the mudline 101. The Piece of subsea equipment 100 may be maneuvered, e.g., by ROV, and additional length of line 104 let out to secure the Piece of subsea equipment 100 in the wellbore. The workboat line 104 is then disconnected from the connector 103.

Illustrative Embodiments

Advantageously, embodiments disclosed herein provide for a method for retrieving and deploying a piece of subsea equipment without the use of a rig. Thus, a system in accordance with embodiments disclosed herein may provide more space and resources for other operations on the rig. Additionally, the method may allow for the retrieval and deployment of a piece of subsea equipment for repair or replacement that is not in close proximity to a rig or FPSO. Lastly, the method may use equipment present in the nearby surroundings such as a workboat, a FPSO, lifting devices, lines, and connectors to perform a new task.

In one embodiment, there is disclosed a method comprising providing a first vessel floating on a surface of a body of water; connecting a first line from the first vessel to a subsea structure; lifting the subsea structure within the body of water; connecting a second line from a second vessel to the subsea structure; disconnecting the first line from the subsea structure; and lifting subsea structure to the second vessel with the second line. In some embodiments, the first line from the first vessel to the subsea structure is connected to at least one subsea buoy to isolate the first vessel's heave from the subsea structure. In some embodiments, the method also includes supporting the subsea structure with a platform on the second vessel, and further comprising disconnecting the second line from the subsea structure. In some embodiments, the method also includes lifting the subsea structure onto a deck of the second vessel. In some embodiments, the method also includes transporting the subsea structure to land. In some embodiments, the first vessel comprises a work boat with at least one of a winch and a crane. In some embodiments, the second vessel comprises an FPSO. In some embodiments, the subsea structure comprises an electrical submersible pump. In some embodiments, the method also includes transporting the subsea structure with the first vessel towards the second vessel a distance from 5 kilometers to 100 kilometers.

In one embodiment, there is disclosed a method comprising providing a first vessel floating on a surface of a body of water; connecting a first line from the first vessel to a subsea structure; lowering the subsea structure within the body of water; connecting a second line from a second vessel to the subsea structure; disconnecting the first line from the subsea structure; moving the second vessel, the second line, and the subsea structure to a desired installation location; and installing the subsea structure at the desired location within the body of water.

While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims. 

1. A method, comprising: providing a first vessel floating on a surface of a body of water; connecting a first line from the first vessel to a subsea structure; lifting the subsea structure within the body of water; connecting a second line from a second vessel to the subsea structure; disconnecting the first line from the subsea structure; and lifting subsea structure to the second vessel with the second line.
 2. The method of claim 1, wherein the first line from the first vessel to the subsea structure is connected to at least one subsea buoy to isolate the first vessel's heave from the subsea structure.
 3. The method of claim 1, further comprising supporting the subsea structure with a platform on the second vessel, and further comprising disconnecting the second line from the subsea structure.
 4. The method of claim 1, further comprising lifting the subsea structure onto a deck of the second vessel.
 5. The method of claim 1, further comprising transporting the subsea structure to land.
 6. The method of claim 1, wherein the first vessel comprises a work boat with at least one of a winch and a crane.
 7. The method of claim 1, wherein the second vessel comprises an FPSO.
 8. The method of claim 1, wherein the subsea structure comprises an electrical submersible pump.
 9. The method of claim 1, further comprising transporting the subsea structure with the first vessel towards the second vessel a distance from 5 kilometers to 100 kilometers.
 10. A method, comprising: providing a first vessel floating on a surface of a body of water; connecting a first line from the first vessel to a subsea structure; lowering the subsea structure within the body of water; connecting a second line from a second vessel to the subsea structure; disconnecting the first line from the subsea structure; moving the second vessel, the second line, and the subsea structure to a desired installation location; and installing the subsea structure at the desired location within the body of water. 